BJTs (bipolar junction transistors) used in switching and amplifying applications include a first pn junction at the boundary between a collector and a base region and a second pn junction at the boundary between the base and an emitter region. The emitter and collector regions have a first conductivity type and the base region a second conductivity type opposite to the first conductivity type. While for most of the semiconductor materials used for BJTs dopant implantation is available for forming the pn junctions, some materials such as silicon carbide SiC show very low dopant diffusion rates and therefore use epitaxy for providing a vertical topology with the collector region, the base region and the emitter regions disposed in a stack on top of each other. Etch processes define the lateral dimensions of the emitter and base regions. The result is a vertical design with the emitter regions formed in mesas. There is a need for providing semiconductor devices including BJT cells with better definable device parameters.